There has been proposed a related-art printing apparatus which equips an image correction function that measures the deviation amount of a position and a density of a formed image and corrects the position and the density to reduce the measured deviation amount. When the image correction function is executed frequently, the quality of the image can be ensured. However, there are disadvantages such as a user has to wait for a long time or consumption of ink and toner is increased, due to especially the measurement of the deviation amount.
Therefore, in the related-art printing apparatus, when a predetermined correction execution condition is satisfied, for example, when a number of pages copied or a time elapsed after a previous image correction function was executed exceeds a predetermined value, the measurement of the deviation amount is executed. In addition, when print data is received during the measurement of the deviation amount, the print data is stored, and after the measurement of the deviation amount is finished, the print data which has been stored is expanded based on the result of the measurement of the deviation amount.
Generally, a related-art printing apparatus expands the print data per page and prints the expanded data successively. Therefore, the correction execution condition may be satisfied during expanding process of the print data per page. However, in the related-art printing apparatus, the way of executing the expanding process when the correction execution condition is satisfied during the expanding process of the print data per page is not considered. For example, if the deviation amount is measured after the expanding process, reflecting the measured deviation amount to the expanding process will be delayed.